Method of making hermetically sealed packages



Feb. 13, 1934.. F; R. CLARK 1,946,569

METHOD OF MAKING HERMETICALLY SEALED PACKAGES Filed March 1, 1932 INVENTOR. BY fiAn c/s 305s ('z/m/r ATTORNEYS.

' wrappers from moisture-proof cellophane.

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Patented Feb. 13, 1934- ATE 1 METHOD ()F MAKENG HERMETKCALHY SEALED PACKAGES Francis Ross Clark, Springfield, Mass, as'signor to Package Machinery Company, Springfield, Masa, a corporation oi lliassachusetts Application March 1, 1932. Serial No. 596,059

3 Claims.

This invention relates to methods of wrapping articles, having particular reference to the production of hermetically sealed packages. The invention is particularly adaptable, although not limited, to the production of hermetically sealed The invention has for its object the production of such hermetically sealed packages by better and simpler operating steps than have been heretofore available. The manner in which these results are secured will appear from the description below taken in connection with the accompanying drawing, in which-- Fig. 1 is a perspective detail illustrating the manner in which the wrapper sheet is prepared and the manner in which it is associated with the article to be wrapped;

Fig. 2 is a bottom view, partially broken away, showing the first wrappingsteps;

Fig. 3 is a perspective view showing the package in the condition of Fig. 2;

Fig. 4 is a view similar to Fig. 3 showing the second wrapping step;

Fig. 5 is a side elevation showing thethird wrapping step;

Fig. 5 is a fragmentary bottom view of the package in the condition of Fig. 5; and

Figs. 7 and 8 are respectively a side elevation and a bottom plan showing the final wrapping step.

In practicing the invention a sheet 10 of wrapping material is'taken of a length sufficient to overlap when folded around the article in one direction, and or a width suflflcient to extend beyond the article ends enough to permit the formation oi the folds hereinafter described. The wrapper is preferably formed of moisture-proof cellophone, as this improves the appearance of the package, assists in the formation of a hermetic seal, and is itself thoroughly water and moistureprooi. Upon this sheet is placed a U-shaped band 11 of sealing liquid, extending around three sides ordy of the sheet and preferably spaced somewhat from its edges. If moisture-proof cellophane is used as a wrapping material the seal ing liouid is preferably a solvent for the coating on the cellophane sheet, a suitable solvent being ethylene glycol monomethyl ether. This solvent has a water-like consistency, and by reason of its lack of viscosity spreads out between two surfaces when these are pressed together. Examples of this action will appear later and the advantages resulting from it will then be described.

The sheet so prepared is folded around the article 12; as shown in Figs. 2 and 3, with the um coated edge 13 adjacent the article and the opposite coated edge 14 overlying it. As the two edges are pressed together the freely flowing solvent spreads out as indicated by the stippled portion in Fig. 2, making a tightlysealed seam out to the edge of the sheet. The package is now in the condition of Fig. 3, in which a tubular extension of the wrapper projecting beyond each end of the article. Within each of theseextensions is a band of solvent 15, corresponding to the sides of the original U-shaped band 11, extending completely around the interior of the tube.

The edges of the two tubular extensions are now infolded as at 16, the tucks being carried way in for a short distance 1'] and then formed Kit on slanting lines 18. This tucking operation brings opposite coated faces of the wrapper into contact, forming an upper two-ply flap 19 and a similar bottom flap 20 which has a portion of threeply thickness due to the overlapping of the ?5 edges 13 and it. At the same time the band of solvent around the inside of the tubular wrapper extension is kept spaced from the article so that no solvent comes in contact with the article end.

At the center of each of these flaps is in some 5 cases (depending upon the dimensions of the article and wrapper and the degree of iniolding of the tucks 16) an exposed coated area 21 of one less ply thickness than the body of the ilap.

The next step is to bring the two flaps 19 and 21 of the lower flap comes into contact partially with the corresponding area of the upper flap and partially with the uncoated folded-over surfaces of the latter. The freely flowing solvent spreads somewhat as the surfaces are brought into con-' tact, with the result that the two flaps are here metically sealed together at all points at which air or moisture might pass from the outside to the inside of the wrapper.

The final step is to bend each flattened compound fiap underneath the package as shown at 23 in Figs. 7 and 8. The solvent on the exposed end of the area 21 of the original upper flap may be sumcient to cause adherence of the compound flap to the body of the package, but in general it will be desirable to add an additional small quantity oi solvent between the compound flaps and the bottom of the package. it is also generally preferable to subject the package to a short application of heat for the purpose of assisting the penetrating and spreading of the solvent and for causing its subsequent evaporation, although a good seal can be made by merely holding the flaps until the solvent has evaporated by itself.

I claim:

1. A method of forming a hermetically sealed package which comprises coating a rectangular sheet of moisture-proof cellulosic material with solvent in a band extending along three of the edges of the sheet, leaving an uncoated margin between the solventand the edges of the sheet, folding the sheet around an article so that the uncoated edge lies adjacent the article and is" responding end flap, turning the compound end flaps thus formed underneath the package, and securing the so folded compound flaps to the body of the package, the solvent acting to soften the coating of the adjoining surfaces to bring them into adherence and spreading through said uncoated margins to produce a seal up to the edges of the sheet.

- 2. A method of forming a hermetically sealed.

package which comprises coating a rectangular sheet of moisture-proof cellulosic material with solvent in a band extending along three of the edges of the sheet, folding the sheet around an article so that the uncoated 'edge lies adjacent the article and is overlapped by the opposite coated edge and so that a band of solvent extends completely around the interior of the tubular wrapper extensions at the ends of the package, tucking in the sides of the tubular extensions part way only towards the package ends so as to leave the' wrapper in "bellows folded condition and prevent contact of the solvent band with the end of the package, pressing the parallel flaps so formed together to form at each end a single compound flap with its superposed plies all hermetically sealed together by the action of the solvent upon the wrapping material, and folding and securing the compound flaps upon a surface of the article. a

3. A method of forming a hermetically sealed package which comprises coating a rectangular sheet of moisture-proof wrappin material with a sealing liquid in a band extending along three of the edges of the sheet, folding the sheet around an article so that the'uncoated edge lies adjacent the article and is overlapped by the opposite coated edge and so that a band of sealing liquid extends completely around the interior of the tubular wrapper extensions at the ends of the package, tucking in the sides of the tubular extensions, part way only towards the package ends so as to leave the wrapper in bellows folded condition and prevent contact of the solvent band with the end of the package, pressing the paral-j lel flaps so formed together to form at each end a single compound flap with its superposed plies all hermetically sealed together, and folding and securing the compound flaps upon a surface of the article.

FRANCIS ROSS CLARK. 

